The First Discourse

Birth is dukkha, sickness is dukkha, death is dukkha, encountering what is not dear is dukkha, separation from what is dear is dukkha, not getting what one wants is dukkha. In brief, these five bundles of clinging* are dukkha.

~The Buddha, in The Dhammacakkappavattana Sutta

*Five Bundles of Clinging (The Five Aggragets or Skandhas)

Form

Sensation

Perception

Mental Formation

Consciousness

Form: The aggregate of form corresponds to what we would call material or physical factors. It includes our own bodies, and material objects as well. Specifically, the aggregate of form includes the five physical organs (eye, ear, nose, tongue, body), and the corresponding physical objects of the sense organs (sight, sound, smell, taste and tangible objects).

Sensation: The aggregate of sensation or feeling is of three kinds - pleasant, unpleasant and neutral. When an object is experienced, that experience takes on one of these emotional tones, the tone of pleasure, the tone of displeasure, or the tone of neutrality.

Perception: The function of perception is to turn an indefinite experience into a definite, recognized and identified experience. It is the formulation of a conception of an idea about a particular object of experience.

Mental Formation: The aggregate of mental formation may be described as a conditioned response to the object of experience. It is not just the impression created by previous actions, but also the responses here and now motivated and directed in a particular way. In short, mental formation or volition has a moral dimension; perception has a conceptual dimension; feeling has an emotional dimension.

Consciousness: Both the eye and the visible object are the physical elements, therefore they are not enough to produce experience by themselves. Only the co-presence of consciousness together with the eye and the visible object produces experience. Similarly, ear, nose, tongue and body are the same. Consciousness is therefore an indispensable element in the product of experience. Consciousness is mere awareness, or sensitivity to an object. When the physical factors of experience, e.g. the eyes and visible objects come in contact, and when consciousness also becomes associated with the physical factors of experience, visual consciousness arises.